Having a weird issue with the fan/blower for the HVAC system. After about an hour of driving the "wind" drops to where there is barely air coming out of the vents...when this happens it doesn't matter what setting is changed, mode, fan speed, auto, dual, heat/AC...still no "wind". However, you can still hear the fan speed change if you change the speed setting...it just doesn't affect how much air comes out of the vent.
If you turn off the hvac completely and leave it for 5-10 minutes it comes back full speed.
I've read about 2 stage resistor? (VBC?) could that be it? Doesn't seem like a fuse, motor or relay issue to me. Any other suggestions where to start troubleshooting?
I HAVE recently recharged my AC system, vacuumed it first, ran a can of oil because those tester things told me to, then recharged with 134a. It cools fine and the system has held pressure since the recharge. But I'm pretty certain I was having the blower issue before the recharge, however it's only an issue on long drives so I tend to forget about it in between, so it's been lurking for a while now.
It's a 2015 SL AWD.